Google on Thursday said it had completed its acquisition of AdMob, six months after it announced its intention to purchase the mobile advertising start-up.

The deal was delayed to make accommodate government regulators, who reviewed the possible antitrust ramifications of allowing the dominant Internet advertising company to take over one of the leading mobile advertising networks.

Last week, the Federal Trade Commission said that it concluded its inquiry and found that the deal was unlikely to harm competition.

The FTC said that Apple's decision to launch its own competing mobile ad network -- through the company's purchase of Quattro Wireless -- figured prominently in its decision.

With the consummation of the deal, Google took the opportunity to reiterate its commitment to mobile advertising.

"It's clear that mobile advertising is becoming a much larger part of our clients' and partners' strategies and with this acquisition, it's now a central part of our own business," said Google VP of product management Susan Wojcicki in a blog post. "In continuing to invest in this highly competitive area, we'll be bringing together our technology, resources and expertise in search advertising with AdMob's innovative solutions for advertising on mobile websites and in mobile applications."

The clarity Wojcicki mentions comes in the form of data: The number of mobile searches Google receives has increased fivefold in the past two years and users of smartphones with Web browsers based on the WebKit layout engine -- the iPhone, Android devices, and the Palm Pre -- searched 62% more in the first three months of the year than in the three months at the end of last year.

It's not just Google that sees profit in the mobile market. It's pretty much everyone in the tech sector, as can be seen from HP's $1.2 billion acquisition of Palm.

Revisiting some of the promising mobile advertising technology previewed at the company’s recent developer conference, Wojcicki pointed to new search ad formats the company has developed, like Click-to-call search ads and expandable rich media ads.

She also highlighted work Google has done to develop alternatives to text-based search, such as spoken queries, queries derived from images, and real-time voice translation.